Lock-stitch shoe-sewing machine.



Patentd Aug. I9, I902.

. A. B. FOWLER. v LOCK STITCH SHOE SEWING MACHINE.

(Application filed. Nov. 4, 1901.)

(No Model.)

fizz/4 A Y m: Norms vmns ca. PHowLiqno. msmnarou. D. c.

' UN'ITE D STATES PATENT OFFICE.

ALFRED B. FOWLER, OF BOSTON, MASSACHUSETTS, ASSIGNOR To UNITED SHOE MACHINERY COMPANY, RATION OF NEW JERSEY.

OF PATEBSON, NEW JERSEY, A CORPO- LOCK-STITCH sHoE-sEwme MACH|NE.. V

SPECIFICATION forming part of Letters Patent No. 707,094, dated Au ust n, 1902.

Application filed November 4,1901. Serial No. 81,066- mama.)

T at whom/it may concern:

Be it known that I, ALFRED B. FOWLER, a citizen of the United States, residing at Boston, in the county ofSuffolk and State of Massachusetts, have invented certain new and V useful Improvements in Lock-Stitch Sewing- Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which it appertains to make and use the same.

The present invention relates generally'toimprovements in lock stitch sewing machines, and more particularly to improvements in lock-stitch machines of the types employed in the leather-working artssuch,

f the stock. There are numerous forms of such pull-01f devices which have been more or less successful in practical operation. All of such devices, however, sofar as I am advised of the prior art, accomplish their pull-ofi operation by engaging the thread between 'the supply and the take-up and deflecting it lat erally, thus exerting thereon not onlya pull in the direction of the supply such as is required to draw thread therefrom, but a sub- 40 stantially equal pull in the opposite direction--that is, toward the Workwhich causes undue strain O11'-.i3h6 work, to obviate which a thread-clamp has commonly been provided, which by suitable actuating mechanism is made to engage the thread-between the pulloff and the take-up and to hold the same during the action of the pull-ofin It has also been found necessary in machines employing a pull-cit as heretofore constructed to provide 59 a clampbetween such pull-0E and the take-up for thefurtheripurposeof positively holding the thread while the take-up is setting the stitch to prevent the take-up. from drawing thread from the supply and to insure the correct positioning jof'the lock in the material.

The present invention consists in the prov. vision in a lock-stitch sewing-machine of a thread-clamp which engages the thread between the supply and the take-up and which accomplishes its pull-off operation by a movement in the direction of the lead of thread, .putting the thread under strain on the supply side only, the clampremainingin engagement with the thread to positively hold the same while the stitch is being set by the take; up. By the arrangement above described I' secure an accurate andefficient' pull-ofiwithout subjecting the thread during thepull-oif operation to a pull'which has any tendency to bring undue strain on the work, and I am enabled to dispense with the thread-clamps and their actuating mechanism, which have heretofore been necessarily provided between the pull-01f and take-up to hold the thread on the work side during the pull-0E operation or for the purpose of holding the thread on the supply side while the take-up sets the stitch.

Another feature of the present invention consists in providing mechanism for actuating the thread-clamp in its thread-pulling movement constructed and arranged to vary the extent of said movement in accordance with the thickness of the stock, so thatmore or less thread is supplied to the stitch-form ing devices'as the thickness of the stock being sewed varies.

4A preferred form of the present invention as applied to a curved hooked-needle lockstitch shoe-sewing machine is illustrated in the accompanying drawings, in whicho Figurel'i'epresentsa side elevation, partially in section, showing, however, only such parts of the sewing-machine as are necessary to illustrate the application of the present invention thereto. Fig.-2 represents avertical 5 ,section takenvonlineA B; Fig. 1. f. I

Like reference-numerals indicate like parts throughout the several views.

The machine of the drawings is provided withlock-stitch-formingmechanism compristoo ing a curved hooked needle 5, mounted in the I the upper jaw 23 being preferably movable usual needle-segment 6, a looper 7, a work table or support 4, and a shuttle 8, all of which parts, together with their actuating mechanism, are supported by a suitable frame 1 and may be and conveniently are of any usual or convenient construction and in themselves form no part of the present invention. I desire to say in this connection that I do not consider any detail description of the parts above referred to necessary in this specification, nor have I illustrated them in detail in the drawings or fully shown their actuating mechanism, all such details being capable of being readily supplied by the machine -designer and clearly understood by any one of average skill in the art.

In connection with the lock-stitch-forming devices above referred to a presser-foot 9 is provided, which presses together the layers of material on the work-table 4 and which rises and falls as the work being sewed varies in thickness, as is usual in the class of devices in the prior art.

Any suitable form of take-up mechanism may be employed in connection with the present invention, that shown in the drawings being an example of a convenient and simple construction,comprising a lever 11,fulcrumed at 12 to the frame 1 and oscillated by a pathcam 14, formed on a cam-disk 3, in which runs a roll 13, carried by the lever 11. The camdisk'3 is mounted upon and driven by the shaft 2the usual cam-shaft or driving-shaft very common in this art. The free end of the lever 11 is pivotally and conveniently adjustably attached to one end of a connecting-link 15, the opposite end of which carries a threadtruck 16, which is reciprocated along a guideslot 17 in the frame 1 by the oscillations of the lever 11. The thread-truck 16 engages the thread between the stationary threadtrucks 18 and 19, over which it leads, and its take-up operation is performed by forming a bight in the thread between said trucks in the usual manner.

So far the description of the machine of the drawings has related to parts of a lock-stitch machine. I will now describe the preferred mechanism whereby my invention may be applied to such machine, it being understood, however, that my invention is not limited thereto, since its construction and organization may be varied at the will of the machinedesigner or to adapt the invention to different forms of lock-stitch machines with the exercise of no more mechanical skill than is possessed by a mechanic having an average knowledge of this art.

Within guides 20 20, secured to or made part of the frame 1, is mounted the slide 21, which is capable of a reciprocating movement in the direction of the lead of the thread from the supply to the stitch-forming devices. The slide 21 carries the clamping-jaws 22 and 23, the lower jaw 22 being preferably stationary upon and rigidly secured to said slide and and normally held in contact with the lower jaw 22 to grip the thread by the spring 50. (See Fig. 2.) The meeting surfaces of the jaws 22 and 23 are preferably corrugated to secure a firm hold of the thread for the purposes hereinafter stated. Asshown, the slide 21 is actuated by a swinging bent lever 24, fulcrumed at 25 on the frame 1 and connected by the link with the slide 21. The lever 24 is provided with a circular adjustmentslot 28, along which the pivotal connection between said lever and the link 30 may be adjusted to vary the extent of the reciprocation imparted to the slide 21 by the swing or oscillating movement of the lever 24. The lever 24 is preferably yieldingly actuated in the direction required to advance the slide 21 toward the stitch-forming devices and cause the clamping-jaws to pull thread from the supply and positively actuated to move the slide 21 in an opposite direction, and to this end one arm of the lever24 is provided with a cam-roll26, which is acted upon byacam 27 on the disk 3, and to the other arm is connected a spring 60, also connected with the frame 1. The above-described arrangement is such that as the cam 27 is rotated to permit the forwad movement of the lever 24 the spring 60, acting therein, advances the slide 21 until such forward movement of lever 24 is stopped, either by the cam 27 or by a stop, as hereinafter described, and since the jaws 22 and 23 normally grip the thread the advance of the slide pulls thread from the supply and gives thread to the stitch forming devices substantially free from strain. After the slide 21 has been advanced to the limit of its forward movement the jaws 22 and 23 remain in engagement and firmly hold the thread until after the take-up has set the stitch, when said jaws are separated to release the thread and the slide 21 returned by the action of the cam 27 to its retracted position, bringing the jaws into position to take a fresh grip on the thread.

The mechanism shown in the drawings for separating the jaws 22 and 23 consists of a bent lever 32, fulcrumed at 33 to the frame 1 and provided with a cam-roll 34, engaging a cam-groove 35 in the cam-disk 3. The free end of the lever 32 is provided with a straight surface, as 36, which is so arranged that when the free end of the lever is raised said surface will be substantially parallel to the line of reciprocation of the slide 21. Thevertically-movable upper jaw 23 is provided with an antifriction-roller 37, arranged above the surface 36 of the lever 32, which roll is engaged by said surface and forced upward when the free end of the lever 32 is raised. The forcing of the roll 37 upward will raise the upper jaw 23 against the tension of the spring and separate the jaws 22 and 23 to release the thread. The surface 36 is of sufficient length to allow the roll 37 to move upon said surface during the entire return movement of the slide 21. The movements of the levers 24 and 32 are so timed with reference to each other and to the operation of the stitch-forming devices that the clampingjaws 22 and 23 will be permitted; to engage and hold the thread during the forward movement of the slide and-will remain in engagement and continue to hold the thread during the time that the slide 21 remains stationary at the end of its forward movement, during which time the take-up is operated to set the stitch. The free end of the lever 32 will be raised and the thread released from the clamping-jaws prior to the time that the lever 24 causes the backward or return movement of the slide 21 and the clamping-jaws. During this return movement of the slide 21 the roll 37 on clamping-jaw 23 will move along the surface 36 andkeep said jaw raised, al-

lowing the thread to run freely between thejaws. The free end of the lever32 will remain raised, and the thread will be released from, the clamping-jaws until just prior to the time that tension-thread is needed for the formation of the stitch, when the lever 32 will be operated, so as to permit the upper jaw 23 to be forced downward by the spring 50 and firmly clamp the thread.

In order to automatically vary the amount of the forward movement imparted to the slide 21,"and consequently the amount of'thread which will be drawn from the thread-supply thereby, so as to, compensate for variations in the thickness of thestockbeing sewed, I provide in the machine of the drawings an adjustable stop, the position of which is con: trolled by the position of the presser-foot 9, which, as before stated, is raised or lowered according to the thickness of the stock. As shown in the drawings, this adjustable stop is constructed and arranged substantially as follows: A bell-crank lever 39 is fulcrumed at 40 to the frame 1. One end of the lever 39 rests upon the upper end of the presser-foot. The opposite end of the lever 39 forms the adjustable stop and is preferably provided with a screw 41, which forms the stop proper and which is screwed through the end'of the lever 39 and provided with a check-nut 42 in order to secure an adjustment of the stop independent of the automatic adjustment thereof caused by the movement of the presserfoot. A spring 42, connected at one end to one end of the lever and at the other end to I a fixed part of the machine, acts to hold the end of the lever 39 in contact with the presserfoot. It is to be noted that the spring 42 must be stronger than the spring 60, so as to hold the end of the lever 39 continuously in contact with the end of the presser-foot. 'As before stated, the lever 24 is swung forward by the action of the spring to advance the slide 21, and if beforeit has reached the limit of its forwardmovement said lever contacts with the screw 41 such forward movement and the advance of the slide 21 is stopped and I the pull-0E operation ceases. The above-described arrangement is such thatwhen the presser-foot 9 is depressed to rest upona thin piece of stock the forward motion of the lever 24 will be arrested proportionately earlier than when the presserfoot rests upon a thicker piece of stock, so that proportionately less thread will be pulled off.

Having thus described my invention, what I claim as new, and desire to secure byLetters Patent, is-

1. A lock-stitch shoe-sewing machine, having, in combination,"stitch-forming "mechanism including a take-up, an intermittentlyacting thread-clamp which en gages'the thread between the supply and the take up and holds the supply end against the pull of the take-up, and means for'moving the threadclamp while closed in the direction of the lead of the thread to pull'off thread froruthe supply, substantially as described.

2. A lock-stitch shoe-sewing machine, having, in combination, stitch for'ming mechanism including a'take-up, an intermittentlyacting thread-clamp which engages the thread between the supply and the take-up and holds. the supply end againstthe'pull of the take-up, and means for moving-the threadclamp while closed in the direction of the lead of the thread to pull ofithread-froni the v supply, said clamp remaining closed-while the stitch is being set by the take-up, substantially as described.

3. A lock-stitch shoe-sewing machine, having, in combination, stitch-forming -mechan-- ism including a take-up, a presser-foot, an intermittently acting thread clamp which engages thethread between the supply and the take up, and means for moving the thread-clamp while closed in the direction of the lead of the'thread a distance governed by 'theposition ofthe'presser-foot to pull oifan amount of thread from the supply proportionalto the thickness of "the work,substantially as described.

In testimony whereof I aflix my signature in presence'of two witnesses; 4 I v I ALERED'B. FO LER. Witnesses: I r

HORAOEV-AN EVEREN, ALFRED H. HILDRETH. 

